Conditional uplink radio resource utilization in a cellular network

ABSTRACT

A communication device receives an uplink grant from a node of a cellular network. The uplink grant indicates uplink radio resources allocated to the communication device in reoccurring time intervals. For each of these time intervals, the communication device selects between an active mode and an inactive mode. In the active mode the communication device performs an uplink transmission in the allocated uplink radio resources. In the inactive mode the communication device performs no uplink transmission in the allocated uplink radio resources.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/897,052 filed 9 Dec. 2015, which is a U.S. National Phase Applicationof PCT/EP2014/068509 filed 1 Sep. 2014. The entire contents of eachaforementioned application is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to methods for controlling radiotransmission in a cellular network and to corresponding devices.

BACKGROUND

In cellular networks, allocation of radio resources to a certain userequipment (UE), also referred to as scheduling, is typicallyaccomplished dynamically on the network side. In the downlink (DL)direction from the cellular network to the UE, a network node mayallocate radio resources in accordance with a need to transmit DL datato the UE. The network node may then inform the UE about the allocatedresources by sending a DL assignment. For the uplink (UL) direction fromthe UE to the cellular network, a scheduling request which is sent bythe UE to the cellular network may be used to indicate that the UE needsradio resources for sending UL data. For example, in the LTE (Long TermEvolution) radio access technology specified by 3GPP (3rd GenerationPartnership Project), a base station of the LTE radio access technology,referred to as “evolved Node B” (eNB) is responsible for the scheduling.This may be accomplished dynamically, taking into account theinstantaneous traffic pattern and radio propagation characteristics ofeach UE.

In the dynamic scheduling process of the LTE radio access technology aUE which needs to send UL data may first send a scheduling request to aneNB which serves the cell of the UE. The scheduling request may be senton a UL control channel, referred to as PUCCH (Physical UL ControlChannel), providing dedicated resources for sending scheduling requestsby the UE. Alternatively, the scheduling request may be sent on acontention based random access channel (RACH). The eNB then allocates ULradio resources to the UE. The allocated UL radio resources areindicated in a UL grant, which is sent from the eNB to the UE. Aseparate UL grant is sent for each subframe or TTI (Transmission TimeInterval) of 1 ms. On the allocated UL radio resources, the UE may thensend UL data to the eNB. In addition, the UE may also send a bufferstatus report (BSR) indicating the amount of buffered UL data still tobe sent by the UE.

In the above process of transmitting the UL data, latency occurs whichis due to the sending of the scheduling request before the UE canproceed with the transmission of the UL data. However, such delay is notdesirable in many cases. For example, certain data traffic may besensitive to latency, such as data traffic associated with onlinegaming.

A technology which may be used for achieving a reduced latency isSemi-Persistent Scheduling (SPS) as specified in 3GPP TS 36.321 V12.2.1(2014-06). In SPS, UL radio resources are periodically allocated to theUE by sending a long lasting grant that which covers multiple TTIs byallocating UL radio resources in a pattern of TTIs with configurableperiodicity. By utilizing SPS, the need to send of scheduling requestsmay be reduced.

However, to achieve a certain latency by utilizing SPS, it may benecessary to configure the allocated SPS UL radio resources with a shortperiodicity. This may result in allocating more UL radio resources tothe UE than actually required. Nonetheless, the UE needs to perform a ULtransmission on ail allocated UL radio resources, which means that ULtransmissions are filled by padding. This sending of padding ULtransmissions may cause undesired energy consumption on the UE side andmay also increase interference.

Accordingly, there is a need for techniques which allow for efficientlycontrolling radio transmissions in a cellular network, in particularwith respect to UL transmissions with low latency.

SUMMARY

According to an embodiment of the invention, a method of controllingradio transmission in a cellular network is provided. According to themethod, a communication device receives a UL grant from the cellularnetwork. The UL grant indicates UL radio resources allocated to thecommunication device in reoccurring time intervals. For each of thesetime intervals, the communication device selects between an active modeand an inactive mode. In the active mode the communication deviceperforms a UL transmission in the allocated UL radio resources. In theinactive mode the communication device performs no UL transmission inthe allocated UL radio resources.

According to a further embodiment of the invention, a method ofcontrolling radio transmission in a cellular network is provided.According to the method, a node of the cellular network sends a UL grantto a communication device. The UL grant indicates UL radio resourcesallocated to the communication device in reoccurring time intervals. Foreach of these time intervals, the node selects between an active modeand an inactive mode. In the active mode the communication deviceperformed a UL transmission in the allocated UL radio resources. In theinactive mode the communication device performed no UL transmission inthe allocated UL radio resources.

According to a further embodiment of the invention, a communicationdevice is provided. The communication device comprises an interface forconnecting to a cellular network. Further, the communication devicecomprises at least one processor. The at least one processor isconfigured to receive a UL grant from the cellular network. The UL grantindicates UL radio resources allocated to the communication device inreoccurring time intervals. Further, the at least one processor isconfigured to, for each of these time intervals, select between anactive mode and an inactive mode. In the active mode the communicationdevice performs a UL transmission in the allocated UL radio resources.In the inactive mode the communication device performs no ULtransmission in the allocated UL radio resources.

According to a further embodiment of the invention, a node for acellular network is provided. The node comprises an interface forconnecting to a communication device. Further, the node comprises atleast one processor. The at least one processor is configured to send aUL grant to the communication device. The UL grant indicates UL radioresources allocated to the communication device in reoccurring timeintervals. Further, the at least one processor is configured to, foreach of these time intervals, select between an active mode and aninactive mode. In the active mode the communication device performed aUL transmission in the allocated UL radio resources. In the inactivemode the communication device performed no UL transmission in theallocated UL radio resources.

According to a further embodiment of the invention, a computer programor computer program product is provided, e.g., in the form of anon-transitory storage medium, which comprises program code to beexecuted by at least one processor of a communication device. Executionof the program code causes the at least one processor to receive a ULgrant from a cellular network. The UL grant indicates UL radio resourcesallocated to the communication device in reoccurring time intervals.Further, execution of the program code causes the at least one processorto, for each of these time intervals, select between an active mode andan inactive mode. In the active mode the communication device performs aUL transmission in the allocated UL radio resources. In the inactivemode the communication device performs no UL transmission in theallocated UL radio resources.

According to a further embodiment of the invention, a computer programor computer program product is provided, e.g., in the form of anon-transitory storage medium, which comprises program code to beexecuted by at least one processor of a node of a cellular network.Execution of the program code causes the at least one processor to senda UL grant to a communication device. The UL grant indicates UL radioresources allocated to the communication device in reoccurring timeintervals. Further, execution of the program code causes the at leastone processor to, for each of these time intervals, select between anactive mode and an inactive mode. In the active mode the communicationdevice performed a UL transmission in the allocated UL radio resources.In the inactive mode the communication device performed no ULtransmission in the allocated UL radio resources.

Details of such embodiments and further embodiments will be apparentfrom the following detailed description of embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically illustrates an exemplary cellular networkenvironment with elements which may be involved in controlling ULtransmissions according to an embodiment of the invention.

FIG. 2 schematically illustrates an exemplary process for performing ULradio transmissions according to an embodiment of the invention.

FIG. 3 schematically illustrates further exemplary process forperforming UL radio transmissions according to an embodiment of theinvention.

FIG. 4 schematically illustrates further exemplary process forperforming UL radio transmissions according to an embodiment of theinvention.

FIG. 5 shows a flowchart for illustrating a method according to anembodiment of the invention, which may be implemented by a communicationdevice.

FIG. 6 shows a flowchart for illustrating a method according to anembodiment of the invention, which may be implemented by a network node.

FIG. 7 schematically illustrates an exemplary sequence of processes whenfor performing UL radio transmissions according to an embodiment of theinvention.

FIG. 8 illustrates an exemplary scenario in which UL radio resounds fromdifferent UL grants are combined according to an embodiment of theinvention.

FIG. 9 illustrates exemplary processes in which sending of referencesignals is controlled according to an embodiment of the invention.

FIG. 10 shows a flowchart for illustrating procedures which may beapplied for controlling reporting by a communication device according toan embodiment of the invention.

FIG. 11 illustrates an exemplary scenario in which release of a UL grantis controlled according to an embodiment of the invention.

FIG. 12 illustrates a further exemplary scenario in which release of aUL grant is controlled according to an embodiment of the invention.

FIG. 13 illustrates a further exemplary scenario in which release of aUL grant is controlled according to an embodiment of the invention.

FIG. 14 illustrates a further exemplary scenario in which a temporaryrelease of a UL grant is controlled according to an embodiment of theinvention.

FIG. 15 illustrates a further exemplary scenario in which a UL grant isreconfigured according to an embodiment of the invention.

FIG. 16 shows a flowchart for illustrating a method according to anembodiment of the invention.

FIG. 17 shows a flowchart for illustrating a further method according toan embodiment of the invention.

FIG. 18 schematically illustrates structures of a communication deviceaccording to an embodiment of the invention.

FIG. 19 schematically illustrates structures of a network node accordingto an embodiment of the invention.

DETAILED DESCRIPTION

In the following, concepts in accordance with exemplary embodiments ofthe invention will be explained in more detail and with reference to theaccompanying drawings. The illustrated embodiments relate to conceptsfor controlling radio transmission in a cellular network. Theembodiments specifically refer to a scenario using LTE radio accesstechnology. However, it should be understood that the concepts couldalso be applied in connection with other radio access technologies,e.g., Universal Mobile Telecommunications System (UMTS) radio accesstechnology.

According to the illustrated concepts, UL transmissions from acommunication device to the cellular network are performed on UL radioresources which may be allocated by two types of UL grants: first ULgrants, in the following referred to as IUA-UL grant (IUA: Instant ULAccess), which each indicate radio resources allocated to thecommunication device in reoccurring time intervals, and second ULgrants, in the following referred to as dynamic UL grant (D-UL grant),which each indicate UL radio resources allocated to the communicationdevice on a one time basis. The radio transmissions may be organized inradio frames each formed of a sequence of subframes, and theabove-mentioned time periods may correspond to the individual subframes.For example, in the LTE radio access technology the time intervals maycorrespond to subframes of 1 ms duration. The IUA-UL grant may beprovided to the communication device in preparation of a future ULtransmission by the communication device, without any indication of aspecific need to transmit UL data by the communication device. Ascompared to that, the D-UL grants are provided to the communicationdevice in a dynamic manner, in particular on an as-needed basis. Forexample, a D-UL grant may be sent in response to a scheduling request bythe communication device or in response to a BSR from the communicationdevice. The IUA-UL grant and the D-UL grants may be sent on a DL controlchannel, such as a PDCCH (Physical DL control channel) of the LTE radioaccess technology. By means of the IUA-UL grants, a low latencyassociated with a UL transmission by the communication device may beprovided. Specifically, on the UL radio resources indicated by theIUA-UL grant, the communication device may perform the UL transmissionwithout previously indicating to the cellular network that there is aneed to transmit UL data, e.g., by sending a scheduling request. Rather,the UL data can be transmitted in the next one of the reoccurring timeintervals.

In the illustrated concepts, the allocated UL radio resources indicatedby the IUA-UL grant are assumed to be utilized in a conditional manner.Specifically, for each of the time intervals the communication deviceselects between an active mode and an inactive mode. In the active mode,the communication device performs a UL transmission on the allocated ULradio resources indicated by the IUA-UL grant. Conditions triggering theselection of the active mode may be a need to send UL data by thecommunication device or a need to send a BSR by the communicationdevice. In the inactive mode, the communication device performs no ULtransmission on the allocated UL radio resources indicated by the IUA-ULgrant. The cellular network expects this behavior of the communicationdevice and correspondingly selects between the active mode and theinactive mode. Specifically, the cellular network may detect that thecommunication device performed a UL transmission on the UL radioresources indicated by the IUA-UL grant and select the active mode toreceive the UL transmission. If the UL transmission is receivedsuccessfully, the cellular network may acknowledge this by sending apositive acknowledgement (ACK) to the communication device. If the ULtransmission not received successfully, the cellular network may notifythis by sending a negative acknowledgement (NACK) to the communicationdevice. For example, sending of such ACKs or NACKs may be performed onthe basis of a HARQ (Hybrid Automatic Repeat Request) protocol, e.g., asdefined for the LTE radio access technology. Further, the cellularnetwork may detect that the communication device performed a ULtransmission on the UL radio resources indicated by the IUA-UL grant andselect the inactive mode. In the latter case, the cellular network mayrefrain from attempting to receive any UL transmission on the UL radioresources indicated by the IUA-UL grant or taking any further actionconcerning such UL transmission, e.g., sending of acknowledgements.

By the conditional utilization of the UL radio resources indicated bythe IUA-UL grant, it can be avoided that the communication device needsto perform a UL transmission in each time interval with UL radioresources allocated by the IUA-UL grant, which allows for energyefficient operation of the communication device and may also avoidunnecessary interference due to the UL transmissions on the UL radioresources indicated by the IUA-UL grant.

FIG. 1 illustrates exemplary elements which may be involved inimplementing a corresponding control of a UL scheduling process. As anexample of a communication device which may connect to the cellularnetwork, FIG. 1 illustrates a UE 10. The UE 10 may correspond to amobile phone, a smartphone, a computer with wireless connectivity, orthe like. As an example of a node of the cellular network which isresponsible for controlling radio transmission by the UE 10, FIG. 1illustrates a base station 100. In accordance with the assumedutilization of the LTE radio access technology, the base station 100will in the following also be referred to as eNB. The eNB 100 is assumedto be responsible for performing the scheduling of UL transmissions, inparticular providing the IUA-UL grants and providing the D-UL grants.

It is to be understood that also other nodes may be involved incontrolling at least a part of the UL scheduling process. For example,when utilizing the UMTS radio access technology, a control node referredto as RNC (Radio Network Controller) could implement similarfunctionalities as explained for the eNB 100.

FIG. 2 shows an exemplary processes of performing UL transmissions onthe basis of the IUA-UL grant. The processes of FIG. 2 involve the UE 10and the eNB 100.

As illustrated, the eNB 100 may send configuration information 201 tothe UE 10. The configuration information 201 may for example indicateradio resources of a UL control channel which are allocated to the UE10, e.g., radio resources of a PUCCH (Physical UL Control Channel).Further, the configuration information could also provide various otherkinds of information for establishing connectivity between the UE 10 andthe eNB 100. The configuration information 201 may also indicate aconfiguration to be utilized by the UE 10 for various kinds of reportingto the cellular network, e.g., reporting of Channel State Information(CSI) or conditions for triggering a BSR. The configuration information201 may for example be sent in an RRC (Radio Resource Control) messageor by some other form of control signaling, e.g., in an MIB (Masterinformation Block) or SIB (System Information Block).

At step 202, the eNB 100 may allocate UL radio resources to the UE 10.Specifically, the eNB 100 allocates these UL radio resources inreoccurring time intervals to the UE 10, e.g., in each subframe or insome other predefined sequence of subframes, such as in every secondsubframe, every third subframe, every fourth subframe, or the like.These UL radio resources may be radio resources of a PUSCH (Physical ULShared Channel).

The eNB 100 then sends an IUA-UE grant 203 to the UE 10. The IUA-ULgrant 203 may be sent on the PDCCH. The IUA-UL grant 203 indicates theUL radio resources allocated at step 202. For example, the allocated ULradio resources may be indicated in terms of one or more resource blocks(RBs). Further, the IUA-UL grant 203 may also indicate a periodicity inwhich the allocated UL radio resources reoccur. Alternatively, suchperiodicity could also be indicated by separate control information,e.g., the control information 201. In FIG. 2, the periodicity in whichthe allocated UL radio resources reoccur is indicated by P,corresponding to a time offset between two time intervals with UL radioresources allocated by the IUA-UL grant. In the following this timeinterval is also referred to as IUA period.

The IUA-UL grant 203 may be provided with an indicator which allows theUE 10 to distinguish the IUA-UL grant 203 from other types of grants,e.g., a D-UL grant. Such indicator may for example be included in aninformation field of the IUA-UL grant 203. Further, the indicator couldalso be provided by utilizing a specific identifier to address theIUA-UL grant to the UE 10, e.g., a specific C-RNTI (Cell Radio NetworkTemporary Identity). For example, a one C-RNTI could be provided foraddressing IUA-UL grants to the UE 10, and one or more other C-RNTIscould be provided for addressing other types of IUA-UL grants to the UE10, such as D-UL grants.

After receiving the IUA-UL grant 203, the UE 10 may enter an IUAoperation, in which the UL radio resources indicated by the IUA UL grant203 may be instantly utilized for performing low latency ULtransmissions. In the IUA operation, the UE 10 checks for each of thetime intervals with the allocated UL resources whether a condition forselecting the active mode is met. If this is the case, the UE 10 selectsthe active mode and performs a UL transmission on the allocated UL radioresources. If this is not the case, the UE 10 selects the inactive modeand performs no transmission on the allocated UL radio resources.

As illustrated by step 204, in the first time interval with allocated ULresources indicated by the IUA-UL grant 203, the UE 10 may select theactive mode to perform a UL transmission on the allocated resourceswhich includes an acknowledgement (IUA-UL grant ACK) 205 of receipt ofthe IUA-UL grant 203 by the UE 10. The IUA-UL grant acknowledgement 205may confirm to the eNB 100 that the UE 10 entered the IUA operation,which for example means that the eNB 100 should expect a UL transmissionon the UL radio resources indicated by the IUA-UL grant 203. The IUA-ULgrant acknowledgement 205 may for example correspond to a IUA-ULtransmission with data padding, i.e., without actual UL data but apredefined or random data pattern, such as only zeros.

As further illustrated by steps 206 and 208, in some time intervals withallocated UL radio resources indicated by the IUA-UL grant 203, the UE10 may select the inactive mode. In this case, the UE 10 performs no ULtransmission on the allocated UL radio resources indicated by the IUA-ULgrant (no IUA-UL TX), as indicated by the dashed arrows 207 and 209.

As further illustrated by step 210, in some time intervals withallocated UL radio resources indicated by the IUA-UL grant 203, the UE10 may select the active mode to perform a UL transmission on theallocated UL radio resources indicated by the IUA-UL grant (IUA-UL TX)211. Selecting the active mode at step 210 may for example be triggeredby a need for transmission of UL data by the UE 10. In such case, theIUA-UL transmission 211 may include at least a part of this UL data anda BSR. Selecting the active mode at step 210 could also be triggered bya need to send a BSR by the UE 10, without a need for transmission of ULdata. In such case, the IUA-UL transmission 211 may include the BSR, butno UL data.

FIG. 3 shows further exemplary processes of performing UL transmissionson the basis of the IUA-UL grant. Also the processes of FIG. 3 involvethe UE 10 and the eNB 100. The processes of FIG. 3 may for example beperformed in the IUA operation of the UE 10, after receiving the IUA-ULgrant.

As indicated by step 301, in a certain time interval with allocated ULradio resources indicated by the IUA-UL grant, the UE 10 may select theactive mode to perform a UL transmission of UL data on the allocated ULradio resources indicated by the IUA-UL grant, in FIG. 3 illustrated byIUA-UL transmission 302 (which may also include a BSR).

In addition to sending the IUA-UL transmission 302, the UE 10 may alsosend a scheduling request 303 to the eNB 100.

As indicated by step 304, in response to the scheduling request 303 theeNB 100 performs allocation of further UL radio resounds 304 to the UE10. The eNB 100 sends a D-UL grant 305 to the UE 10 which indicatesthese further allocated UL radio resources.

In the processes of FIG. 3, it is further assumed that the IUA-ULtransmission 302 could not be successfully received by the eNB 100,e.g., due to poor radio link adaptation between the UE 10 and the eNB100. Accordingly, the eNB 100 notifies the UE 10 of the failed receptionby sending a HARQ NACK 306.

The HARQ NACK 306 causes the LTE 10 to retransmit the UL data on thefurther allocated UL radio resources indicated by the D-UL grant 305, asindicated by dynamic UL transmission (D-UL TX) 307. Similar to IUA-ULtransmission 302, also the D-UL transmission 307 may include a BSR.

In the processes of FIG. 3, sending the scheduling request 305 togetherwith the initial IUA-UL transmission 302 allows for avoiding additionaldelays if the IUA-UL transmission fails, i.e., for achieving a similarperformance with respect to latency as in the case of utilizing onlyscheduling request based dynamic scheduling.

FIG. 4 shows further exemplary processes of performing UL transmissionson the basis of the IUA-UL grant. Also the processes of FIG. 4 involvethe UE 10 and the eNB 100. The processes of FIG. 4 may for example beperformed in the IUA operation of the UE 10, after receiving the IUA-ULgrant.

As indicated by step 401, in a certain time interval with allocated ULradio resources indicated by the IUA-UL grant, the UE 10 may select theactive mode to perform a UL transmission of UL data on the allocated ULradio resources indicated by the IUA-UL grant, in FIG. 4 illustrated byIUA-UL transmission 402. As illustrated, the IUA-UL transmission 402also includes a BSR. The BSR indicates an amount of further UL datapending for transmission by the UE 10.

As indicated by step 403, on the basis of the BSR in IUA-UL transmission402, the eNB 100 performs allocation of further UL radio resources tothe UE 10. The eNB 100 sends a D-UL grant 404 to the UE 10 whichindicates these further allocated UL radio resources.

The UE 10 may then transmit at least a part of the further UL data onthe further allocated UL radio resources indicated by the D-UL grant404, as indicated by D-UL transmission 405. Also D-UL transmission 405includes a BSR which indicates an amount of further UL data pending fortransmission by the UE 10.

As indicated by step 406, on the basis of the BSR in D-UL transmission405, the eNB 100 performs allocation of further UL radio resources tothe UE 10. The eNB 100 sends a further D-UL grant 407 to the LTE 10which indicates these further allocated UL radio resources.

The UE 10 may then transmit at least a part of the further UL data onthe further allocated UL radio resources indicated by the D-UL grant407, as indicated by D-UL transmission 408. Again, D-UL transmission 408includes a BSR which indicates an amount of further UL data pending fortransmission by the UE 10.

As further illustrated, the UE 10 may also perform a further IUA-ULtransmission 409 at the later time interval with allocated UL radioresources indicated by the IUA-UL grant. Again, IUA-UL transmission 409includes a BSR which indicates an amount of further UL data pending fortransmission by the UE 10.

As can be seen from the processes of FIG. 4, the BSR in a IUA-ULtransmission may trigger allocation of further UL radio resources whichmay then be indicated in a D-UL grant. These further allocated UL radioresources may then be used alternatively or in addition to the UL radioresources indicated by the IUA-UL grant for transmission of UL data. Inthis way, the amount of UL radio resources allocated to the UE 10 may bedynamically adapted to the current UL traffic demand of the UE 10, whileat the same time allowing fast initial access to UL radio resources.

FIG. 5 shows a flowchart for illustrating a method which may be utilizedfor controlling a communication device, e.g., the UE 10, to operate inaccordance with the above-mentioned concepts. If a processor basedimplementation of the communication device is used, the steps of themethod may be performed by one or more processors of the communicationdevice. For this purpose, the processor(s) may execute correspondinglyconfigured program code. Further, at least some of the correspondingfunctionalities may be hardwired in the processor(s).

At step 510, the communication device receives the IUA-UL grant. Thecommunication device may receive the IUA-UL grant on a DL controlchannel, e.g., on the PDCCH of the LTE radio access technology. TheIUA-grant indicates UL radio resources allocated to the communicationdevice in reoccurring time intervals, e.g., corresponding to a periodicpattern of subframes.

As indicated by step 520, the communication device may then acknowledgereceipt of the IUA-UL grant, e.g., by performing a UL transmissionfilled by padding on the allocated UL radio resources indicated in theIUA-UL grant.

The communication device may then enter the IUA operation and performthe following actions when reaching a next time interval with allocatedUL radio resources indicated in the IUA-UL grant, as indicated by step530.

At step 540, the communication device may check if a D-UL grant wasreceived by the communication device. If this is the case, theutilization of the D-UL grant may be prioritized over the utilization ofthe IUA-UL grant, corresponding to an overriding of the IUA-UL grantwith the D-UL grant, and the method may proceed with step 545, asindicated by branch “Y”.

At step 545, further UL radio resources indicated by the D-UL grant maybe utilized for performing a D-UL transmission. If no UL data areavailable for transmission, the D-UL transmission may include a BSR, butno UL data.

For the next time interval, the method may then return to step 530.

If at step 540 no DLL grant was received by the communication device,the method may proceed with step 550, as indicated by branch “N”.

At step 550, the communication device may check if UL data need to betransmitted by the communication device. If this is the case, the methodmay proceed with step 555, as indicated by branch “Y”.

At step 555, the communication device selects the active mode andperforms an IUA-UL transmission on the UL radio resources indicated inthe IUA-UL grant. This IUA-UL transmission includes at least a part ofthe UL data and may further include a BSR. For the next time interval,the method may then return to step 530.

If at step 550 there is no need for transmission of UL data, the methodmay proceed with step 560, as indicated by branch “N”.

At step 560, the communication device may check whether a triggercondition for sending a BSR is fulfilled. If this is the case, themethod may proceed with step 565, as indicated by branch “Y”.

At step 565, the communication device selects the active mode andperforms an IUA-UL transmission on the UL radio resources indicated inthe IUA-UL grant. This IUA-UL transmission includes a BSR, but no ULdata. For the next time interval, the method may then return to step530.

If at step 560 no trigger condition for sending a BSR is fulfilled, themethod may proceed with step 570, as indicated by branch “N”.

At step 570, the communication device selects the inactive mode andperforms no IUA-UL transmission on the UL radio resources indicated inthe IUA-UL grant. For the next time interval, the method may then returnto step 530.

FIG. 6 shows a flowchart for illustrating a method which may beimplemented by a node of the cellular network, e.g., the eNB 100, tocontrol a communication device in accordance with the above-mentionedconcepts. If a processor based implementation of the node is used, thesteps of the method may be performed by one or more processors of thenode device. For this purpose, the processor(s) may executecorrespondingly configured program code. Further, at least some of thecorresponding functionalities may be hardwired in the processor(s).

At step 610, the node sends the IUA-UL grant to the communicationdevice. The node may send the IUA-UL grant on a DL control channel,e.g., on the PDCCH of the LTE radio access technology. The IUA-grantindicates radio resources allocated to the communication device inreoccurring time intervals, e.g., corresponding to a periodic pattern ofsubframes.

As indicated by step 620, the node may then receive an acknowledgementof receipt of the IUA-UL grant by the communication device. For example,the acknowledgement may be indicated by a padded UL transmission on theallocated UL radio resources indicated in the IUA-UL grant.

The node may then enter the IUA operation and perform the followingactions when reaching a next time interval with allocated UL radioresources indicated in the IUA-UL grant, as indicated by step 630.

At step 640, the node may check if the communication device performed anIUA-UL transmission on the UL radio resources indicated in the IUA-ULgrant. For this purpose, the node may for example detect a signal levelon the UL radio resources. If the signal level is above a threshold, thenode may determine that the communication device performed an IUA-ULtransmission on the UL radio resources indicated in the IUA-UL grant.

If at step 640 no IUA-UL transmission on the UL radio resourcesindicated in the IUA-UL grant is detected, the method may return to step630 for the next time interval, as indicated by branch “N”.

If at step 640 an IUA-UL transmission on the UL radio resourcesindicated in the IUA-UL grant is detected, the method may continue withstep 650, as indicated by branch “Y”.

At step 650, the node may receive the IUA-UL transmission. As mentioned,above the IUA-UL TX may also include a BSR. Further, the IUA-ULtransmission may include UL data.

At step 660, the node may check if the BSR indicates that an amount ofUL data to be transmitted by the communication device is abovethreshold. The threshold may be preconfigured or may be calculated in adynamic manner, e.g., on the basis of a HARQ roundtrip time T_(HRTT), inunits of the time periods with allocated UL resources indicated by theIUA-UL grant (i.e., in units of the IUA period), and a size S_(IUAG) ofthe IUA-UL grant, i.e., the data capacity of the allocated UL radioresources indicated by the IUA-UL grant. For example, the threshold maybe calculated according to:Threshold=THRTT*SIUAG+A,  (1)

where A may be a constant or function that may be used to ensure thatsending a D-UL grant is only triggered if the amount of UL data still tobe sent after the HARQ roundtrip time T_(HRTT) is not too small.

If at step 660 the amount of UL data to be transmitted is not above thethreshold, the method may return to step 630 for the next time interval,as indicated by branch “N”.

If at step 660 the amount of UL data to be transmitted is above thethreshold, the method may continue with step 670, as indicated by branch“Y”.

At step 670, the node may check if a D-UL grant was already sent to thecommunication device, but not yet utilized. If this is the case, themethod may return to step 630 for the next time interval, as indicatedby branch “Y”.

If at step 670 it is found that there is no D-UL grant which was sent tothe communication device, but not yet utilized, the method may continuewith step 680 as indicated by branch “N”.

At step 680, the node may send a new D-UL grant to the communicationdevice. The size S_(DG) of this new D-UL grant may be determined on thebasis of amount of data V_(B) indicated in the BSR and the size S_(IUAG)of the IUA-UL grant, e.g., according to:S _(DG) =V _(B) −T _(HRTT) *S _(IUAG).  (2)

After sending the D-UL grant at step 680, the method may return to step630 for the next time interval.

By the checks in steps 660 and 670 of FIG. 6, it can be avoided that aD-UL grant is sent to the communication device which is actually notrequired. Specifically, the check of step 660 may ensure that the D-ULgrant is sent if transmission of the UL data is on the UL radioresources indicated in the IUA-UL grant is not possible before the D-ULgrant is received by the communication device.

FIG. 7 shows further a typical sequence of processes for performing ULtransmissions on the basis of the IUA-UL grant. Also the processes ofFIG. 7 involve the UE 10 and the eNB 100.

In the processes of FIG. 7, initially the eNB 100 sends a IUA-UL grant701 to the LTE 10. The IUA-UL grant 701 indicates UL radio resourcesallocated to the UE 10 in reoccurring time intervals. In the example ofFIG. 7, it is assumed that these IUA UL radio resources are allocated ineach subframe. The IUA-UL grant 701 may be sent on the PDCCH.

The UE 10 then performs an initial IUA-UL transmission with an IUA-ULgrant acknowledgement 702. If the UE 10 has no UL data to transmit, theIUA-UL grant acknowledgement 702 may be a IUA-UL transmission withpadding. The IUA-UL grant acknowledgement 702 confirm receipt of theIUA-UL grant 701 to the eNB 100. If the IUA-UL grant acknowledgement 702is not received by the eNB 100, the eNB 100 may resend the IUA-UL grant701. The usage of the IUA-UL grant acknowledgement 702 is optional andmay for example be configured during connection configuration, e.g., bythe control information 201 of FIG. 2. The IUA-UL grant 701 may be validfor an open time period, e.g., until de-configured by the eNB 100.Alternatively, also a validity period could be indicated together withthe IUA-UL grant 701 or in separate control information, such as thecontrol information 201 of FIG. 2.

When UL data for transmission becomes available at the UE 10, the UE 10,as indicated by 703, the UE 10 may prepare one or more IUA-ULtransmissions on the allocated UL radio resources of the IUA-UL grant.FIG. 7 also illustrates a corresponding processing time, e.g.,associated with layer 2 and layer 1 processing. If a BSR is triggered,the UE 10 may also add the BSR to the IUA-UL transmissions.

The UE 10 then sends the IUA-UL transmission(s) 704, 705 at the nexttime intervals with UL radio resources indicated by the IUA-UL grant.

When the eNB 100 receives the IUA-UL transmissions 704, 705 it mayevaluate the included BSR to decide whether sending of one or more D-ULgrants to the UE 10 is appropriate, e.g., using processes as explainedin connection with FIG. 6.

In the illustrated example, the eNB 100 sends D-UL grants 706 and 707 tothe UE 10. As further illustrated, these D-UL grants 706, 707 may beaccompanied by HARQ feedback with respect to the IUA-UL transmissions704, 705.

While performing the IUA-UL transmissions 704, 705 and transmitting theD-UL grants 706, 707, the LTE 10 and the eNB 100 may accomplish linkadaptation of the radio link between the UE 10 and the eNB 100, e.g., byselecting a suitable modulation and coding scheme (MCS) and/ortransmission power. This link adaptation phase may last for about oneHARQ roundtrip time, e.g., eight subframes. After that, a higherperformance may be achieved due to optimized link adaptation.

The UE 10 may then continue performing UL transmissions on the furtherallocated radio resources indicated by the D-UL grants 706, 707, asillustrated by D-UL transmissions 708 and 709. As illustrated, the D-ULtransmissions 708, 709 may each include a BSR, so that further D-ULgrants may be issued to the UE 10 as long as it has UL data fortransmission.

As mentioned above, the IUA-UL grant and D-UL grants may be utilized inparallel. In particular, the IUA-UL grant may be utilized to provide abasic allocation of UL radio resources which allows for fast initialaccess without a preceding scheduling request. The D-UL grants may inturn be utilized provide further allocated UL radio resources if thereis a higher traffic demand by the UE 10.

For achieving a more efficient utilization of the allocated UL radioresources, utilization of the D-UL grants may be prioritized over theutilization of the IUA-UL grant in time intervals where both types ofgrants indicate allocated UL radio resources. This prioritization mayfor example be achieved by performing the check of step 540 in FIG. 5.

In some scenarios, the UL radio resources indicated by a D-UL grant fora certain time interval could be overlapping with the UL radio resourcesindicated by the IUA-UL grant. Since in typical scenarios the D-UL grantindicates a larger amount of UL radio resources, a D-UL transmission onthe UL radio resources indicated by D-UL grant may be more efficient. Ifat least a part of the UL radio resources indicated by the IUA-UL grantare non-overlapping with the UL radio resources indicated by the D-ULgrant, it is also possible to combine these non-overlapping UL radioresources with the UL radio resources indicated by the D-UL grant andperform the UL transmission on both types of UL radio resources. Anexample of a corresponding scenario is illustrated in FIG. 8.

In the scenario of FIG. 8, the eNB 100 sends IUA-UL grant 801 to the UE10, e.g., on the PDCCH. Later, the eNB 100 sends D-UL grant 802 to theUE. Initially, the UE 10 performs IUA-UL transmissions 803, 804, 805 onUL resources indicated by fee IUA-UL grant 801. In FIG. 8, these ULradio resources are referred to as IUA-RB. However, after a certainprocessing delay, additional utilization of the UL radio resourcesindicated in the D-UL grant, in FIG. 8 referred to as D-RB, becomespossible. In each TTI, the UE 10 may then perform a single D-ULtransmission 806, 807 on the UL radio resources indicated in both theIUA-UL grant and the D-UL grant, i.e., on IUA-RB and D-RB. Thecombination of the UL radio resources can be achieved on the networkside by preparing the D-UL grant 802 to cover both IUA-RB and D-RB.Further, such combination of the UL radio resources can be achieved onthe UE side by adding the UL radio resources indicated in the IUA-grant801 to the UL radio resources indicated in the D-UL grant 802 whenpreparing the D-UL transmissions 806, 807.

The utilization of the IUA-UL grant may also be considered whenconfiguring the transmission of reference signals, e.g., soundingreference signals (SRS), by the UE 10. Such reference signals may beutilized for UL channel quality estimation and link adaptation purposes.For example, by configuring additional reference signal transmissions,the eNB 100 may be provided with a better estimate of the UL channelquality, in particular when the LTE only sparsely performs IUA-ULtransmissions. An example of processes where SRS transmissions areconfigured for the UE 10 and utilized when performing IUA-ULtransmissions is illustrated in FIG. 9.

As illustrated by step 901, the eNB 100 determines an SRS configurationfor the UE 10. This may for example be performed when the UE 10 entersthe cellular network or if radio connectivity of the UE 10 to thecellular network otherwise changes. The SRS configuration of step 901may define a periodic pattern of sending periodic SRS and/or triggerevents for sending aperiodic SRS. In the processes of FIG. 9, it isassumed that one such trigger events for sending aperiodic SRS isreception of a IUA-UL grant. The eNB 100 then sends configurationinformation 902 indicating the determined SRS configuration to the UE10. The configuration Information 902 may for example be sent in an RRCmessage.

As illustrated by step 903, the eNB 100 may then determine an IUA-ULgrant. This determination of the IUA-UL grant may for example involveselecting UL radio resources allocated to the UE 10. The determinationof the IUA-UL grant may be based on an initial assumption on the ULchannel quality between the UE 10 and the eNB 100. The eNB 100 thensends the IUA-UL grant 904 to the UE 10, e.g., on the PDCCH.

As indicated by step 905, at the UE 10 receipt of the IUA-UL grant 904triggers sending of an IUA-UL transmission 906 and a transmission ofaperiodic SRS 907. The aperiodic SRS can be wideband or frequencyhopping. As mentioned above, the IUA-UL transmission 906 may have thepurpose of acknowledging receipt of the IUA-UL grant 904.

The aperiodic SRS transmission 907 may in turn be utilized forperforming measurements to obtain a better estimate of the UL channelquality between the UE 10 and the eNB 100. This better estimate may thenbe utilized as a basis for re-determining the IUA-UL grant of the UE 10,as illustrated by step 908. For example, the measurement could indicatea low UL channel quality, and step 908 could involve adding further ULradio resources in the IUA-UL grant to allow for utilizing a more robustcoding scheme for the IUA-UL transmissions. The eNB 100 then sends there-determined IUA-UL grant 909 to the UE 10.

As indicated by step 910, at the UE 10 receipt of the re-determinedIUA-UL grant 909 again triggers sending of an IUA-UL transmission 911and a transmission of aperiodic SRS 912. Again, the aperiodic SRS can bewideband or frequency hopping. The IUA-UL transmission 911 may have thepurpose of acknowledging receipt of the IUA-UL grant 909. The aperiodicSRS transmission 912 may be utilized for performing measurements toobtain a new estimate of the UL channel quality between the UE 10 andthe eNB 100. In the scenario of FIG. 9 it is assumed that the newestimate of the UL channel quality prompts no further re-determinationof the IUA-UL grant.

After that, the LTE 10 may continue its IUA operation, which may alsoinvolve sending periodic SRS 913, 914 as configured at step 901. Theseperiodic SRS may be utilized by the eNB 100 for keeping track of the ULchannel quality between the UE 10 and the eNB 100 and more reliablyreceiving IUA-UL transmissions.

For the DL direction, the LTE 10 may need to send CSI, such as CQI(Channel Quality Indicator) reports, RI (Rank Indicator) reports, or PMI(Preceding Matrix Indicator) reports to the cellular network. Suchreports may also be sent in IUA-UL transmissions, or alternatively on aUL control channel, e.g., the PUCCH. An example of procedures which mayutilized for considering the IUA-UL transmissions in CSI reporting isillustrated by the flowchart of FIG. 10.

As illustrated in FIG. 10, at step 1010 the UE 10 may enter the cellularnetwork. This may involve establishing basic connectivity between theLTE 10 and the eNB 100, e.g., configuring a DL control channel, such asa PDCCH, and/or configuring a UL control channel, such as a PUCCH.

At step 1020, the UE 10 may receive a CM reporting configuration, e.g.,in configuration information from the eNB 100, such as the configurationinformation 201 of FIG. 2. The CSI reporting configuration may forexample define one or more periodicities of sending CSI reports.Further, the CSI reporting configuration may defined resources of the ULcontrol channel which may be utilized for sending CSI reports.

At step 1030, the UE 10 receives the IUA-UL grant, e.g., on the PDCCH.As mentioned above, the IUA-grant indicates UL radio resources allocatedto the UE 10 in reoccurring TTIs, e.g., in a periodic pattern of TTIs.

The UE 10 may the enter the IUA operation and according to a CSIreporting periodicity as for example configured at step 1020, repeatedlyperform the following actions:

At step 1040, the UE 10 detects that, according to the CSI reportingperiodicity, a condition for sending a CSI report is met.

At step 1050, the UE 10 may then check if there are UL data fortransmission by the UE 10. If this is the case, the procedures maycontinue with step 1060, as indicated by branch “Y”. At step 1060, theUE 10 may append the CSI to a IUA-UL transmission of the UL data.

If at step 1050 there are no UL data for transmission by the LTE 10, theprocedures may continue with step 1070, as indicated by branch “N”. Atstep 1070, the UE 10 may send the CSI report on a UL control channel,e.g., on resources as configured at step 1020.

After step 1060 or 1070, the procedures may continue with step 1080,where CSI counters may be reset or CSI parameters may be updated. Thismay for example also involve performing measurements on referencesignals from the eNB 100. For the next CSI reporting period, theprocedures may then return to step 1040.

The UL radio resources allocated by the IUA-UL grant can be released invarious ways. For example, eNB 100 can explicitly indicate the releasein control information sent to the UE 10, e.g., on a DL control channel,such as the PDCCH. The UE 10 may then stop the IUA operation and nolonger utilize the UL radio resources indicated in the IUA-UL grant.Further, the UE 10 may acknowledge the release by sending an indicationto the eNB 100. This may be accomplished in an explicit manner bysending corresponding control information to the eNB 100, e.g., on a ULcontrol channel, such as the PUCCH or on a UL data channel, such as thePUSCH. The release may also be implicitly acknowledged by sending afinal IUA-UL transmission with padding. The eNB 100 may interpret thisIUA-UL transmission as implicit acknowledgement of the release.

As a further possibility, also sending of a D-UL grant may be utilizedto trigger the release of the UL radio resources indicated by the IUA-ULgrant. For example, a rule could be defined that the release istriggered if the UL radio resources indicated by the D-UL grant and theUL radio resources indicated by the IUA-UL grant are overlapping.Further, the D-UL grant could include an information field indicatingthat the IUA-UL grant is to be released. In some scenarios, any D-ULgrant received by the UE 10 could trigger the release.

In some scenarios, the release of the IUA-UL grant may also beimplicitly triggered at the UE 10. For example, the UL resources can beimplicitly released after a configured number of unused occasions forperforming a IUA-UL transmission. An example of a corresponding scenariois illustrated in FIG. 11.

In the scenario of FIG. 11, it is assumed that the IUA-UL grantallocates UL radio resources in every second TTI (TTI 2, 4, 6, 8, . . .). Further, utilization of a release rule is assumed, according to whichthe UL radio resources indicated by the IUA-UL grant are released aftertwo unused occasions for performing a IUA-UL transmission. The TTIswhich are utilized for sending a IUA-UL transmission are shown as shadedboxes. As can be seen, IUA-UL transmissions are performed in TTIs 2 and4, while no IUA-UL transmissions are performed in TTIs 6 and 8.Accordingly, since the occasions for performing an IUA-UL transmissionsin TTI 6 and 8 were left unused, in TTI 8 the UE 10 releases the ULradio resources indicated by the IUA-UL grant.

As another example of a release rule, the UL resources may be implicitlyreleased when a certain count of unused IUA-UL transmission occasions isreached after a timer expired which had been started, e.g., when thelast UL transmission happened or when no UL data was available anymore.This way, both potential new UL data that may become available in agiven amount of time as well as a number of occasions to use the ULradio resources of the IUA-UL grant resources after the timer expiry maybe considered in combination.

As another example of a release rule, a timer may be started when theIUA-UL grant is received, and the UL radio resources of the IUA-UL grantmay be released upon expiry of this timer. Alternatively, instead ofutilizing a timer, occasions for performing IUA-UL transmissions couldbe counted (from the receiving the IUA-UL grant) and when a configurednumber is reached, the UL radio resource of the IUA-UL grant may bereleased.

As another example of a release rule, when counting the number of unusedoccasions for performing an IUA-UL transmission, those occasions inwhich D-UL transmissions were performed (overriding the IUA-UL grant)may be left uncounted. An example of a corresponding scenario isillustrated in FIG. 12.

In the scenario of FIG. 12, it is assumed that the IUA-UL grantallocates UL radio resources in every second TTI (TTI 2, 4, 6, 8 . . .). Further, utilization of a release rule is assumed, according to whichthe UL radio resources indicated by the IUA-UL grant are released aftertwo unused occasions for performing a IUA-UL transmission, not countingthose occasions in which the IUA-UL grant was overridden by a D-UL grantfor the same TTI. The TTIs which are utilized for sending a IUA-ULtransmission or D-UL transmission are shown as shaded boxes.

As illustrated in FIG. 12, a D-UL grant overrides the IUA-UL grant inTTI 6. Still, the UL radio resources of the IUA-UL grant are onlyreleased in subframe 10, i.e., after two unused occasions for performinga IUA-UL transmission, where TTI 6 is not regarded as an unused occasionfor performing a IUA-UL transmission.

As another example of a release rule, a D-UL grant overriding the IUA-ULgrant may trigger the release. An example of a corresponding scenario isillustrated in FIG. 13.

In the scenario of FIG. 13, it is assumed that the IUA-UL grantallocates UL radio resources in every second TTI (TTI 2, 4, 6, 8, . . .). Further, utilization of a release rule is assumed, according to whichthe UL radio resources indicated by the IUA-UL grant are released by aD-UL grant overruling the IUA-UL grant. As illustrated in FIG. 13 a D-ULgrant overrides the IUA-UL grant in TTI 6. Accordingly, the UL radioresources of the IUA-UL grant are released in TTI 6.

Irrespective of the applied release rule, the LTE 10 may indicate therelease to the eNB 100, For example, this may be accomplished in anexplicit manner by sending corresponding control information to the eNB100, e.g., on a UL control channel, such as the PUCCH or on a UL datachannel, such as the PUSCH. The release may also be indicated by sendinga final IUA-UL transmission with padding. The eNB 100 may interpret thisIUA-UL transmission as indication of the release.

The indication of the release informs the cellular network about therelease, which enables utilization of the released UL radio resourcesfor other purposes, e.g., allocation to other UEs.

In some scenarios, the release does not need to be indicated, but may bedetected by the eNB 100 on the basis of the release rule as applied bythe UE 10. For example, similar to the UE 10, the eNB 100 could monitora counter for the number of unused occasions for performing an IUA-ULtransmission or could monitor a timer started when sending the IUA-ULgrant.

In some scenarios, the release of the UL resources of the IUA-UL grantmay be only temporary. In other words, the IUA operation of the UE 10could be suspended or paused, to be resumed at a later point of time.

Resuming of the IUA operation may be triggered by explicit signaling orimplicitly. For example, the resuming of the IUA operation may betriggered a configurable time period after the release, a configurabletime period after the last IUA-UL transmission, or a configurable timeperiod after when no more UL data was available for transmission. Suchtime periods may also be defined in terms of the time intervals betweenoccasions for IUA UL transmissions, i.e., in terms of the IUA period. Anexample of a corresponding scenario is shown in FIG. 14.

In the scenario of FIG. 14, it is assumed that the IUA-UL grantallocates UL radio resources in every second TTI (TTI 2, 4, 6, 8, . . .). Further, utilization of a release rule is assumed, according to whichthe UL radio resources indicated by the IUA-UL grant are temporarilyreleased after two unused occasions for performing a IUA-ULtransmission. The TTIs which are utilized for sending a IUA-ULtransmission are shown as shaded boxes. As can be seen, IUA-ULtransmissions are performed in TTIs 2 and 4, while no IUA-ULtransmissions are performed in TTIs 6 and 8. Accordingly, since theoccasions for performing an IUA-UL transmissions in TTI 6 and 8 wereleft unused, in TTI 8 the UE 10 temporarily releases the UL radioresources Indicated by the IUA-UL grant. In TTIs 10 and 12 the IUAoperation is paused, and then resumed in TTI 14, in which an IUA-ULtransmission is performed again.

Resuming the IUA operation may also optionally be indicated to the eNB100, e.g., by sending an explicit indication or padding in the firstIUA-UL transmission after resuming the IUA operation.

In some scenarios, resuming of the IUA operation may also be triggeredafter a configurable time period or a configurable number of IUA periodsfrom the last performed IUA-UL transmission. In some scenarios, resumingof the IUA operation may also be triggered after a configurable time ornumber of IUA periods from transmission of the IUA-UL grant,irrespective of performed IUA-UL transmissions.

The implicit release of the UL radio resources indicated in the IUA-ULgrant allows for performing the release an efficient manner, e.g.,without requiring excessive signaling overhead. Further, the releaseprovides a possibility to react to changing load or channel conditionsfor the UE 10, e.g., to optimize system capacity.

Instead of releasing the UL resources of the IUA-UL grant, it is alsopossible to reconfigure the periodicity of the IUA-UL grant. For examplethe IUA period may controlled to increase, such as according to anexponential function as illustrated in the example of FIG. 15 in which afirst IUA periodicity is 2 TTIs, a second IUA periodicity is 4 ms, and athird IUA periodicity is 8 ms. Other functions or patterns defining theincrease could be applied as well. In the example of FIG. 15, theincrease of the IUA period is assumed to be triggered already attransmission of the IUA-UL grant. Alternatively, the increase could betriggered instead of the release in the above-mentioned release rules.

FIG. 16 shows a flowchart for illustrating a method of controlling radiotransmission in a cellular network. The method may be used forimplementing the above-described concepts in a communication device withconnectivity to the cellular network, e.g., the UE 10. If a processorbased implementation of the communication device is used, the steps ofthe method may be performed by one or more processors of thecommunication device. For this purpose, the processor(s) may executecorrespondingly configured program code. Further, at least some of thecorresponding functionalities may be hardwired in the processor(s).

At step 1610, the communication device receives a UL grant from thecellular network. The communication device may receive the UL grant on aUL control channel, e.g., a PDCCH of the LTE radio access technology.The UL grant indicates UL radio resources allocated to the communicationdevice in reoccurring time intervals. Examples of such UL grant are theIUA-UL grants 203, 701, 801, and 903. The time intervals may reoccurperiodically. However, other patterns of reoccurrence could be utilizedas well. A periodicity in which the time intervals reoccur may beindicated in the UL grant or in separate control information transmittedto the communication device, such as in the configuration information201 of FIG. 2 or in the configuration information 901 of FIG. 9. Thetime intervals may correspond to TTIs in which radio transmission in thecellular network is organized. For example, in the LTE radio technologythe radio transmission may be organized in radio frames each subdividedinto subframes, and the time intervals may correspond to subframes. Theallocated UL radio resources may be radio resources of a UL datachannel, such as a PUSCH of the LTE radio access technology.

At step 1620, the communication device selects between an active modeand an inactive mode. This selection is performed for each of the timeintervals with allocated UL radio resources indicated at step 1610. Inthe active mode the communication device performs a UL transmission inthe allocated UL radio resources. In the inactive mode the communicationdevice performs no UL transmission in the allocated UL radio resources.Accordingly, the utilization of the UL radio resources allocated by theUL grant of step 1610 is conditional.

The selection of step 1620 may involve that the communication devicechecks whether UL data is available for transmission by thecommunication device. In response to UL data being available fortransmission, the communication device may select the active mode toperform a UL transmission which includes at least a part of the UL data.

In response to UL data being available for transmission, thecommunication device may also send a scheduling request to the cellularnetwork, thereby requesting allocation of further UL radio resources tothe communication device. An example of such scheduling request is thescheduling request 303.

Further, the selection of step 1620 may involve that the communicationdevice checks whether one or more conditions for sending a BSR,indicating an amount of UL data available for transmission, by thecommunication device, are met. In response to one or more of suchconditions being met, the communication device may selecting the activemode to send a UL transmission including the BSR.

If the active mode was selected at step 1620, the communication deviceperforms a UL transmission at step 1630. The UL transmission may includethe UL data and/or the BSR as mentioned in connection with step 1620.Examples of such UL transmissions are the IUA-UL transmissions 211, 302,402, 410, 704, 705, 803, 804, and 805. If the inactive mode was selectedat step 1620, the communication device performs no UL transmission onthe allocated UL radio resources indicated at step 1610.

In some scenarios, in response to receiving the UL grant at step 1610,the communication device may also send a message for acknowledgingreceipt of the UL grant to the cellular network. For this purpose, thecommunication device may select the active mode in a first one of thetime intervals to send a UL transmission including the message foracknowledging receipt of the UL grant. Examples of such UL transmissionsare the IUA-UL transmissions 205, 702, 906, and 911.

In some scenarios, receipt of the UL grant at step 1610 may cause thecommunication device to send one or more reference signals to thecellular network. An example of such reference signals are the aperiodicSRS as explained in connection with FIG. 9.

In some scenarios the UL transmission sent at step 1630 may include anindication of a channel quality experienced by the communication device,e.g., a CSI report as explained in connection with FIG. 10.

In some scenarios, the communication device may also receive a furtherUL grant which indicates further UL radio resources allocated to thecommunication device in one of the time intervals. Examples of suchfurther UL grant are the D-UL grants 305, 404, 408; 706, 707, and 802.The communication device may then perform a UL transmission in acombination of the further UL radio resources allocated by this furtherUL grant and at least a part of the UL radio resources allocated by theUL grant of step 1610. An example of such combined utilization of the ULradio resources allocated by different UL grants is explained inconnection with FIG. 8.

At step 1640, the communication device may reconfigure the UL radioresources allocated by the UL grant of step 1610. This may for exampleinvolve changing a periodicity of the time intervals with the allocatedUL radio resources, e.g., as explained in connection with the scenarioof FIG. 15. The reconfiguration of step 1610 may be triggered accordingto a rule configured in the communication device, similar to the releaserules explained in connection with FIGS. 11, 12, 13, and 14. Further,the reconfiguration could be triggered by receipt of the UL grant atstep 1610 or by control information from the cellular network.

At step 1650, the communication device may release the UL radioresources allocated by the UL grant of step 1610. The communicationdevice may release the al located UL radio resources in response toreceiving control information from the cellular network. Further, thecommunication device may release the allocated UL radio resources inresponse to expiry of a configured time period. Such time period mayalso be defined in terms of periods in which the allocated UL radioresources reoccur. Further, the communication device may release theallocated UL radio resources in response to a number of the timeintervals, in which the communication device performed no transmissionon the allocated UL resources, reaching a threshold. Examples ofcorresponding release rules for implicitly controlling release of the ULradio resources are explained in connection with FIGS. 11 to 13. Thecommunication device may also indicate the release of the allocated ULradio resources to the cellular network, e.g., by sending correspondingcontrol information or by performing a UL transmission with padding onthe UL radio resources.

In some scenarios, the release of the UL radio resources may betemporary, i.e., utilization of the UL radio resources by thecommunication device may be paused or suspended. Accordingly, aftertemporarily releasing the UL radio resources at step 1650, thecommunication device may resume utilization of the allocated UL radioresources at step 1660. This resumption may be in response to receivingcontrol information from the cellular network. Further, the resumptionof utilization of the allocated UL radio resources may also be inresponse to expiry of a configured time period. Such time period mayalso be defined in terms of periods in which the allocated UL radioresources reoccur. The time period may start at a certain event, e.g.,receipt of the UL grant at step 1610, temporary release of the allocatedUL radio resources at step 1650, or last utilization of the allocated ULradio resources by the communication device. The communication devicemay also indicate the resumption of utilization of the allocated ULradio resources to the cellular network, e.g., by sending correspondingcontrol information or by performing a UL transmission with padding onthe UL radio resources.

FIG. 17 shows a flowchart for illustrating a method of controlling radiotransmission in a cellular network. The method may be used forimplementing the above-described concepts in a node of the cellularnetwork, e.g., in a node which is responsible for schedulingtransmissions, such as the eNB 100 or an RNC when using the UMTS radioaccess technology. If a processor based implementation of the node isused, the steps of the method may be performed by one or more processorsof the node. For this purpose, the processors) may executecorrespondingly configured program code. Further, at least some of thecorresponding functionalities may be hardwired in the processor(s).

At step 1710, the node sends a UL grant to a communication device. Thenode may send the UL grant on a DL control channel, e.g., a PDCCH of theLTE radio access technology. The UL grant indicates UL radio resourcesallocated to the communication device in reoccurring time intervals.Examples of such UL grant are the IUA-UL grants 203, 701, 801, and 903.The time intervals may reoccur periodically. However, other patterns ofreoccurrence could be utilized as well. A periodicity in which the timeintervals reoccur may be indicated in the UL grant or in separatecontrol information transmitted to the communication device, such as inthe configuration information 201 of FIG. 2 or in the configurationinformation 901 of FIG. 9. The time intervals may correspond to TTIs inwhich radio transmission in the cellular network is organized. Forexample, in the LTE radio technology the radio transmission may beorganized in radio frames each subdivided into subframes, and the timeintervals may correspond to subframes. The allocated UL radio resourcesmay be radio resources of a UL data channel, such as a PUSCH of the LTEradio access technology.

The node may send the UL grant in response to detecting a change of aconnection status of the communication device, e.g., when thecommunication device enters the cellular network and connects thereto,when the communication device enters a different cell or area of thecellular network, or the like. Further, the node may send the UL grantaccording to a periodic schedule, e.g., every minute or hour. In eachcase, no request for the UL grant by the communication device isrequired.

At step 1720, the node device selects between an active mode and aninactive mode. This selection is performed for each of the timeintervals with allocated UL radio resources indicated at step 1710. Inthe active mode the communication device performed a UL transmission inthe allocated UL radio resources. In the inactive mode the communicationdevice performed no UL transmission in the allocated UL radio resources.Accordingly, the node decides for each of the time intervals whether thecommunication device performed a transmission on the allocated UL radioresources. This may for example be accomplished by detecting signalsfrom the communication device in the allocated UL radio resources. Inresponse to detecting no signals from the communication device in theallocated UL radio resources, the node may select the inactive mode. Inresponse to detecting signals from the communication device in theallocated UL radio resources, the node may select the active mode.

If the active mode was selected at step 1720, the node may receive a ULtransmission from the communication device at step 1730. The ULtransmission may include UL data and/or a BSR indicating an amount of ULdata available for transmission by the communication device. Examples ofsuch UL transmissions are the IUA-UL transmissions 211, 302, 402, 410,704, 705, 803, 804, and 805. If the inactive mode was selected at step1720, the node does not attempt receiving a UL transmission on theallocated UL radio resources indicated at step 1710 and also refrainsfrom performing any further action associated with such possible ULtransmission, e.g., sending feedback for notifying the communicationdevice of a missing UL transmission.

In some scenarios, the node may use the BSR in the UL transmission as abasis for sending a further UL grant to the communication device. Thefurther UL grant indicates further UL radio resources allocated to thecommunication device in one of the time intervals. Examples of suchfurther UL grant are the D-UL grants 305, 404, 408; 706, 707, and 802.An example of a process for controlling the provision of the further ULgrant is explained in connection with FIG. 6. The node may then receivea UL transmission in a combination of the further UL radio resourcesallocated by this further UL grant and at least a part of the UL radioresources allocated by the UL grant of step 1710. An example of suchcombined utilization of the UL radio resources allocated by different ULgrants is explained in connection with FIG. 8.

In some scenarios, the node may also expect a message for acknowledgingreceipt of the UL grant sent at step 1710. In response to not receivingsuch message, the node may resend the UL grant. In some scenarios, thenode may select the active mode in a first one of the time intervals toreceive a UL transmission including the message for acknowledgingreceipt of the UL grant. Examples of such UL transmissions are theIUA-UL transmissions 205, 702, 906, and 911.

In some scenarios, receipt of the UL grant sent at step 1710 may causethe communication device to send one or more reference signals to thecellular network. An example of such reference signals are the aperiodicSRS as explained in connection with FIG. 9. The node may then adapt aradio link to the communication device on the basis of the referencesignals or modify the UL grant, e.g., as explained in connection withFIG. 9.

In some scenarios the UL transmission received at step 1730 may includean indication of a channel quality experienced by the communicationdevice, e.g., a CSI report as explained in connection with FIG. 10. Thenode may then adapt a radio link to the communication device on thebasis of the indicated channel quality, e.g., as explained in connectionwith FIG. 10.

At step 1740, the node may detect that the communication deviceperformed a reconfiguration of the UL radio resources allocated by theUL grant of step 1710. This reconfiguration may for example involvechanging a periodicity of the time intervals with the allocated UL radioresources, e.g., as explained in connection with the scenario of FIG.15. The reconfiguration of step 1710 may be triggered according to arule configured in the communication device, similar to the releaserules explained in connection with FIGS. 11, 12, 13, and 14, and thenode may apply a corresponding rule for detecting the reconfiguration.The reconfiguration may also be detected on the basis of an indicationfrom the communication device.

At step 1750, the node may detect that the communication deviceperformed a release of the UL radio resources allocated by the UL grantof step 1710. The communication device may have released the allocatedUL radio resources in response to expiry of a configured time period.Such time period may also be defined in terms of periods in which theallocated UL radio resources reoccur. Further, the communication devicemay have released the allocated UL radio resources in response to anumber of the time intervals, in which the communication deviceperformed no transmission on the allocated UL resources, reaching athreshold. Examples of corresponding release rules for implicitlycontrolling release of the UL radio resources are explained inconnection with FIGS. 11 to 13. The node may apply corresponding rulesfor detecting the release, e.g., detect the release on the basis ofexpiry of a configured time period or on the basis of a number of saidtime intervals, in which the communication device performed notransmission on the allocated UL resources, reaching a threshold.

In some scenarios, the communication device may also indicate therelease of the allocated UL radio resources to the node, e.g., bysending corresponding control information or by performing a ULtransmission with padding on the UL radio resources. The node may thendetect the release on the basis of the indication from the communicationdevice.

In some scenarios, the release of the UL radio resources may betemporary, i.e., utilization of the UL radio resources by thecommunication device may be paused or suspended. Accordingly, after thetemporary release of the UL radio resources of step 1750, thecommunication device may resume utilization of the allocated UL radioresources. The node may detect this resumption at step 1760. Theresumption of utilization of the allocated UL radio resources may be inresponse to expiry of a configured time period. Such time period mayalso be defined in terms of periods in which the allocated UL radioresources reoccur. The time period may start at a certain event, e.g.,receipt of the UL grant at step 1710, temporary release of the allocatedUL radio resources, or last utilization of the allocated UL radioresources by the communication device. The node may apply correspondingrules for detecting the resumption at step 1760, e.g., detect theresumption on the basis on the basis of expiry of a configured timeperiod.

The communication device may also indicate the resumption of utilizationof the allocated UL radio resources to the cellular network, e.g., bysending corresponding control information or by performing a ULtransmission with padding on the UL radio resources. The node may thendetect the resumption on the basis of the indication from thecommunication device.

It is to be understood that the methods of FIGS. 16 and 17 may becombined, e.g., in a system including a communication device operatingaccording to the method of FIG. 16 and a node operating according to themethod of FIG. 17.

FIG. 18 illustrates exemplary structures which may be used forimplementing the above concepts in a communication device, e.g., the UE10.

As illustrated, the communication device may include an interface 1810for connecting to a cellular network. For example, the interface maycorrespond to a radio interface as specified for the LTE radio accesstechnology or based on another radio access technology, such as the UMTSradio access technology. The interface 1810 may be utilized forreceiving the above-mentioned UL grants or for sending UL transmissions.Further, the interface 1810 may be utilized for receiving controlinformation from the cellular network or sending control information tothe cellular network.

Further, the communication device includes one or more processors 1850coupled to the interface 1810, and a memory 1860 coupled to theprocessor(s) 1850. The memory 1860 may include a read-only memory (ROM),e.g., a flash ROM, a random-access memory (RAM), e.g., a dynamic RAM(DRAM) or static RAM (SRAM), a mass storage, e.g., a hard disk or solidstate disk, or the like. The memory 1860 includes suitably configuredprogram code to be executed by the processor(s) 1850 so as to implementthe above-described functionalities of the communication device. Inparticular, the memory 1860 may include various program code modules forcausing the communication device to perform processes as describedabove, e.g., corresponding to the method steps of FIG. 16. Asillustrated, the memory 1860 may include a IUA control module 1870 forimplementing the above-described functionalities of conditionallyutilizing the UL radio resources allocated in reoccurring timeintervals. Further, the memory 1860 may include a transmission controlmodule 1880 for implementing the above-described functionalities ofcontrolling the sending of UL transmissions from the communicationdevice, e.g., on the UL radio resources in the reoccurring timeintervals. Further, the memory 1860 may include a control module 1890for implementing generic control functionalities, e.g., controllingreporting or other signaling.

It is to be understood that the structures as illustrated in FIG. 18 aremerely schematic and that the communication device may actually includefurther components which, for the sake of clarity, have not beenillustrated, e.g., further interlaces or processors. Also, it is to beunderstood that the memory 1860 may include further types of programcode modules, which have not been illustrated, e.g., program codemodules for implementing known functionalities of a UL. According tosome embodiments, also a computer program may be provided forimplementing functionalities of the communication device, e.g., in theform of a physical medium storing the program code and/or other data tobe stored in the memory 1860 or by making the program code available fordownload or by streaming.

FIG. 19 illustrates exemplary structures which may be used forimplementing the above concepts in a node of a cellular network, e.g.,the eNB 100.

As illustrated, the node may include an interface 1910 for connecting toa communication device. The interface 1910 may be utilized for sendingthe above-mentioned UL grants or for receiving UL transmissions.Further, the interface 1910 may be utilized for sending controlinformation to the communication device or receiving control informationfrom the communication device. If the node is implemented as a basestation, such as the eNB 100, the interface 1910 may be a radiointerface for establishing a radio link to a communication device. Ifthe node is implemented as a control node of a base station, such as anRNC of the UMTS radio access technology, the interface 1910 may be usedfor controlling the base station and for sending or receivingtransmissions by the communication devices via the base station.

Further, the node includes one or more processors 1950 coupled to theinterface 1910, and a memory 1960 coupled to the processor(s) 1950. Thememory 1960 may include a ROM, e.g., a flash ROM, a RAM, e.g., a DRAM orSRAM, a mass storage, e.g., a hard disk or solid state disk, or thelike. The memory 1960 includes suitably configured program code to beexecuted by the processors) 1950 so as to implement the above-describedfunctionalities of the communication device. In particular, the memory1960 may include various program code modules for causing the node toperform processes as described above, e.g., corresponding to the methodsteps of FIG. 17. As illustrated, the memory 1960 may include a IDAcontrol module 1970 for implementing the above-described functionalitiesof determining a UL grant allocating UL resources in reoccurring timeintervals and controlling the utilization of such UL grant. Further, thememory 1960 may include a dynamic scheduling module 1980 forimplementing the above-described functionalities of dynamically sendingUL grants with respect to a certain time interval. Further, the memory1960 may include a control module 1990 for implementing generic controlfunctionalities, e.g., controlling reporting or other signaling.

It is to be understood that the structures as illustrated in FIG. 19 aremerely schematic and that the node may actually include furthercomponents which, for the sake of clarity, have not been illustrated,e.g., further interfaces or processors. Also, it is to be understoodthat the memory 1960 may include further types of program code modules,which have not been illustrated, e.g., program code modules forimplementing known functionalities of an eNB or RNC. According to someembodiments, also a computer program may be provided for implementingfunctionalities of the node, e.g., in the form of a physical mediumstoring the program code and/or other data to be stored in the memory1960 or by making the program code available for download or bystreaming.

As can be seen, the concepts as described above may be used forachieving a low latency for UL transmissions by a communication device.Specifically, by allowing conditional utilization of the UL radioresources allocated in reoccurring time intervals, an energy efficientoperation of the communication device and low interference level may beachieved.

It is to be understood that the examples and embodiments as explainedabove axe merely illustrative and susceptible to various modifications.For example, the illustrated nodes may be implemented by a single deviceor by a system of multiple devices. Moreover, it is to be understoodthat the above concepts may be implemented by using correspondinglydesigned software to be executed by one or more processors of anexisting device, or by using dedicated device hardware.

What is claimed is:
 1. A method of operation by a communication device,the method comprising: receiving an uplink grant from a cellularnetwork, the uplink grant indicating uplink radio resources allocated tothe communication device in reoccurring time intervals, the uplink radioresources allocated to the communication device in each time intervalfor use in performing an uplink transmission of at least one of uplinkdata and a buffer status report; and for each of the reoccurring timeintervals: in response to determining that the communication device doesnot need to transmit uplink data or a buffer status report for the timeinterval, selecting an inactive mode in which the communication devicedoes not perform an uplink transmission on the uplink radio resourcesallocated to the communication device in the time interval.
 2. Themethod of claim 1, further comprising, for each of the reoccurring timeintervals, in response to determining that the communication deviceneeds to transmit uplink data or a buffer status report for the timeinterval, selecting an active mode in which the communication deviceperforms an uplink transmission on the uplink radio resources allocatedto the communication device in the time interval.
 3. The method of claim2, further comprising transmitting a scheduling request to the cellularnetwork in response to the amount of the uplink data exceeding theamount accommodated by the uplink radio resources allocated to thecommunication device in the time interval, the scheduling requestrequesting that additional uplink radio resources be allocated to thecommunication device.
 4. The method of claim 2, further comprisingreceiving a non-acknowledgment from the cellular radio networkindicating that the cellular network did not successfully receive atleast a portion of the uplink data transmitted by the communicationdevice on the uplink radio resources allocated to the communicationdevice in the time interval, and, in response to the non-acknowledgment,sending a scheduling request to the cellular network, requesting thatadditional uplink radio resources be allocated to the communicationdevice for performing a retransmission in response to thenon-acknowledgment.
 5. A communication device, comprising: an interfaceconfigured for wirelessly communicating with a cellular network; andprocessing circuitry operatively associated with the interface andconfigured to: receive an uplink grant from the cellular network, theuplink grant indicating uplink radio resources allocated to thecommunication device in reoccurring time intervals, the uplink radioresources allocated to the communication device in each time intervalfor use in performing an uplink transmission of at least one of uplinkdata and a buffer status report; and for each of the reoccurring timeintervals: in response to determining that the communication device doesnot need to transmit uplink data or a buffer status report for the timeinterval, select an inactive mode in which the communication device doesnot perform an uplink transmission on the uplink radio resourcesallocated to the communication device in the time interval.
 6. Thecommunication device of claim 5, wherein, for each of the reoccurringtime intervals, in response to determining that the communication deviceneeds to transmit uplink data or a buffer status report for the timeinterval, selecting an active mode in which the communication deviceperforms an uplink transmission on the uplink radio resources allocatedto the communication device in the time interval.
 7. The communicationdevice of claim 6, wherein the processing circuitry is configured totransmit a scheduling request to the cellular network in response to theamount of the uplink data exceeding the amount accommodated by theuplink radio resources allocated to the communication device in the timeinterval, the scheduling request requesting that additional uplink radioresources be allocated to the communication device.
 8. The communicationdevice of claim 6, wherein, in response to receiving anon-acknowledgment from the cellular radio network indicating that thecellular network did not successfully receive the at least a portion ofthe uplink data transmitted by the communication device on the uplinkradio resources allocated to the communication device in the timeinterval, the processing circuitry is configured to send a schedulingrequest to the cellular network, requesting that additional uplink radioresources be allocated to the communication device for performing aretransmission in response to the non-acknowledgment.
 9. A method ofoperation by a node in a cellular network, the method comprising:sending, to a communication device, an uplink grant indicating uplinkradio resources allocated to the communication device in reoccurringtime intervals, the uplink radio resources allocated to thecommunication device in each time interval for use in performing anuplink transmission of at least one of uplink data and a buffer statusreport; and for each of said time intervals, selecting an inactive modeof operation at the node, in response to detecting that thecommunication device did not transmit on the uplink radio resources,wherein the communication device decides whether to transmit on theuplink radio resources allocated in the time interval in dependence onwhether the communication device has uplink data or a buffer statusreport to send, and wherein, in the inactive mode, the node does notattempt to receive any uplink transmission from the communication deviceon the uplink radio resources.
 10. The method of claim 9, furthercomprising, for each of said time intervals, selecting an active mode ofoperation at the node, in response to detecting that the communicationdevice did transmit on the uplink radio resources, wherein, in theactive mode, the node attempts to receive an uplink transmission fromthe communication device on the uplink radio resources.
 11. The methodof claim 10, further comprising, in conjunction with the node attemptingto receive the uplink transmission from the communication device on theuplink radio resources, sending an indication for the communicationdevice, indicating whether the uplink transmission was successfullyreceived by the node.
 12. The method of claim 10, further comprising, inresponse to the uplink transmission from the communication device on theuplink radio resources including a Buffer Status Report (BSR) thatindicates a need for a further allocation of uplink radio resources tothe communication device, sending a further uplink grant to thecommunication device, granting uplink radio resources to thecommunication device that are in addition to the uplink radio resourcesgranted to the communication device in the reoccurring time intervals.13. A node configured for operation in a cellular network, the nodecomprising: an interface configured for wirelessly communicating with acommunication device operating in the cellular network, the uplink radioresources allocated to the communication device in each time intervalfor use in performing an uplink transmission of at least one of uplinkdata and a buffer status report; and processing circuitry operativelyassociated with the interface and configured to: send, to thecommunication device, an uplink grant indicating uplink radio resourcesallocated to the communication device in reoccurring time intervals; andfor each of said time intervals, select an inactive mode of operation atthe node, in response to detecting that the communication device did nottransmit on the uplink radio resources, wherein the communication devicedecides whether to transmit on the uplink radio resources allocated inthe time interval in dependence on whether the communication device hasuplink data or a buffer status report to send, and wherein, in theinactive mode, the node does not attempt to receive any uplinktransmission from the communication device on the uplink radioresources.
 14. The node of claim 13, wherein, for each of said timeintervals, the processing circuitry is configured to select an activemode of operation at the node, in response to detecting that thecommunication device did transmit on the uplink radio resources, andwherein, in the active mode, the node attempts to receive an uplinktransmission from the communication device on the uplink radioresources.
 15. The node of claim 14, wherein, in conjunction with thenode attempting to receive the uplink transmission from thecommunication device on the uplink radio resources, the processingcircuitry is configured to send an indication for the communicationdevice, indicating whether the uplink transmission was successfullyreceived by the node.
 16. The node of claim 14, wherein, in response tothe uplink transmission from the communication device on the uplinkradio resources including a Buffer Status Report (BSR) that indicates aneed for a further allocation of uplink radio resources to thecommunication device, the processing circuitry is configured to send afurther uplink grant to the communication device, granting uplink radioresources to the communication device that are in addition to the uplinkradio resources granted to the communication device in the reoccurringtime intervals.